Shale retorting apparatus



July 21,y 1959 w. l.. BEWLEY ET AL 2,895,885

sHALE RETORTING APPARATUS Filed March 22, 1956 United States Patent OSHALlE RETORTING APPARATUS William L. Bewley, John L. Hotz, and RobertL. Switzer, Long Beach, Calif., assignors to Union Oil Company ofCalifornia, Los Angeles, Calif., a corporation of California ApplicationMarch 22, 1956, Serial No. 573,287

4 Claims. (Cl. 202-91) This invention relates to improvements in solidsuid contacting and particularly to an improved process and apparatus forthe production of hydrocarbon gases and oils from solids by thermalmeans. Applicable solids include such oil-producing and oil-containingmaterials as oil shale, tar sand, oil-saturated diatomite, bituminousand sub-bituminous coals, and the like. The description will beconducted in terms of the eduction of shale oil and gas from oil shalefor the sake of simplicity and with the understanding that the processand apparatus are applicable in general to other solids from which oilsand gases can be produced, and to solids-fluid contacting processes ingeneral.

Some processes for the eduction of shale oils and gases involve thedownward passage of shale rock as a moving bed by gravity through avertical heat treating kiln. During this passage they are heated toeduction temperatures by direct or indirect means. From a thermalefciency standpoint the direct heating means is preferred in which acountercurrent contact of hot gases with the shale rock is employed. Toavoid the large fuel consumption otherwise required, most of theseprocesses involve the direct injection of air or other oxygencontaininggas into the bottom of the kiln to burn the carbonaceous residue fromthe spent shale. This generates hot flue gases needed to heat the rock.However, some diificulties are encountered with the fusion of the spentshale due to this burning, and frequently the fused or partially fusedrock plugs the air inlet requiring a shutdown. Since all of thehydrocarbon product is removed at the top of the kiln, it must beremoved as a vapor and thus the process requires extensive cooling andcondensing facilities.

Other shale eduction processes have successfully avoided the large fueland condensing water requirements by utilizing an upllow of shale rockand a downflow of heating gas. The shale is fed upwardly successivelythrough a perforated product fluid-shale rock disengaging section and aheat treating and kiln section. Air or other oxygen-containing gasenters the top of the heat treating section, is preheated in cooling thehot shale ash, burns the carbonaceous residue from the spent shale, andthe hot flue gases continue downwardly to heat the shale rock toeduction temperatures. The hydrocarbon oils and gases are thus evolvedin the eduction zone. The whole vapor phase passes downwardly in directcontact Iwith the raw shale, and is cooled thereby condensing thehydrocarbon oil and preheating the raw shale. The liquid and gaseousproducts are `drawn off at the top o f the disengaging section and arethus separated from the upwardly moving shale rock. A solids feederpasses the shale rock upwardly through the disengaging and heat treatingsections and displaces the shale ash out the top of the unit. Theprocess supplies its own fuel in the form of carbonaceous spent shale.It cools and partially condenses its own product in preheating the rawshale rock.

One principal problem of these processes involves the presence of solidslines in the solids to be thermally Vice treated and in the presentillustration these fines are exemplified by shale nes in the feed. Inthe downliowy solids processes, a screening step is required to separatefrom the rock fed to the process the shale fines whose, averagedimensions are less than about 0.25 inch. In the upflow shale process,the problem is aggravated with screw feeders, and non-vertically actingpiston feeders; are employed. With such solids feeders it has beenlfound that the quantity of lines in the feed increases as much as ormore when such solids feeders are employed and that up to about 50% ofthe feed is re duced to fines. In the present invention a verticalreciprocating piston feeder, hereinafter more fully described, is used.This piston feeder successfully passes shale rock upwardly through theapparatus of this invention With-` out the formation of substantialquantities of additional lines, The process and apparatus are alsocapable of a substantialll complete retorting of valuable products fromthose lines which naturally occur in the unscreened feed and thus theyaccomplish what all the previous retorting processes were incapable ofaccomplishing.

The present invention is therefore directed to an m-` proved upow shaleretorting process as illustrative of those solids heat treatingprocesses in which the solids; are passed upwardly countercurrent to adownilow of heat treating fluid and in which process steps and appa-`ratus elements are utilized to avoid the necessity of solidsV finesseparation from the feed and to obtain a complete and uniform heattreatment of all solids including the lines.

It is thus a primary object of this invention to provide an improvedsolids-huid contacting process.

It is an additional object to provide a particularly improved solidsupow and fluid downilow heat treating process especially adapted to theproduction of hydro-Y carbon gases and oils from solids.

It is a more specific object of this invention to provide an improvedprocess for the retorting of shale including shale nes to effect asubstantially complete recovery of shale oil and gas from the shale rockincluding the shale fines.

It is also an object of this invention to provide an apparatus adaptedto accomplish the aforementioned objects.

Other objects and advantages of this invention become apparent to thoseskilled in the art as the description thereof proceeds.

The present invention Will be more readily understood by reference tothe accompanying drawings in which:

Figure 1 is a side elevation view in partial cross section of theimproved apparatus of this invention shown in conjunction with aschematic flow diagram of the process,`

Figure 2 is an end elevation view of the central portion of theapparatus shown in Figure l, and

Figure 3 is a cross section plan view of the intermediate section shownin Figure 2.

Referring now more particularly to Figure l, the proc-l ess of thepresent invention will be described in terms of a specific example ofthe present invention as applied to the retorting of oil shale toproduce shale oil and shale gas. The apparatus of the present inventionconsists essentially of three parts; namely an upper heat treating oreduction kiln 10, an intermediate solids-Huid disengaging section 12,and a lower reciprocating piston shale feeder contained within feederhousing 14.

Shale feeder housing 14 contains a vertically reciprocating feederpiston 16 contained within feeder cylinder 18. Cylinder 18 oscillates ina vertical plane about trun nion 20a so that it may be moved between thevertical feeding position shown and an inclined cylinder chargfl ingposition not shown but in which the upper outlet opening of cylinder 18is disposed to the left and imniediately below the lower outlet openingof shale feed hopper 20. A hydraulic actuating cylinder 22 disposedwithin cylinder 18 reciprocates feeder piston 16 in cylinder 18. Asecond hydraulic cylinder 24 contained within feeder case 14 oscillatesfeeder cylinder 18 between the filling and feeding positions. A V-shapedtrough 15 runs' along the bottom of the case and has a screw conveyor 17at its apex to move settled fines toward outlet 19. A stream of oil isintroduced into case 14 through line 23 controlled by valve 25 andserves to flush the nes slurry from outlet 19 through line 27. Thisslurry is returned to hopper 20 by pump 29 and line 31 to recycle fines.

A Raw shale is introduced by any convenient conveyor means not shown inthe direction indicated into feed hopper 20. With feeder piston 16disposed at its upper extremity immediately after its up stroke,cylinder 18 is moved to a point in alignment with feed hopper 20.Cylinder 22 retracts piston 16 drawing a charge of shale rock into theupper part of feeder cylinder 18. Hydraulic cylinder 24 is then extendedreturning feeder cylinder 18 to the vertical position shown. Thenhydraulic cylinder 22 is extended forcing piston 16 upwardly therebymoving the charge of rock into disengaging section 12 and displacing therock therein and in kiln upwardly. This cycle is repeated therebycontinuously feeding fresh shale at the bottom of the structure anddisplacing cool shale ash from the top.

The shale ash is displaced as described from the top of kiln 10 andinside housing 26. It falls by gravity through the paths indicated as byarrows 28 and 30 downwardly on to the bottom 30 of housing 26 anddischarges through outlet 32 into ash disposal conveyor 34.

Kiln 10 is provided with a plurality of radial ns 36 disposed on itsoutside surface. Jacket 38 surrounds the outer edges of the finsproviding a series of adjacent nearvertical paths for cooling air whichpasses by natural or forced convection upwardly within jacket 38, intomanifold 40, and then out through stack 42 to the atmosphere. Ifdesired, this warm air may at least in part be introduced into the topof the kiln through line 44 together with other gases subsequentlydescribed.

The raw shale is passed by means described above upwardly through gasand liquid disengaging section 12 in which the cool ue and shale gasesand the condensed shale oil are disengaged from the upwardly moving massof shale. In vkiln 10 the upwardly moving shale passes successivelythrough a fresh shale preheating and product cooling and condensingzone, a shale eduction zone, a spent shale combustion zone, and a shaleash cooling and gas preheating zone. At this point the ashes areexpelled as described from the top of kiln 10. In order to support thecarbonaceous spent shale combustion, an oxygen-containing gas such asair is introduced through line 44 at a rate controlled by valve 46. Withthis gas may be mixed steam or water or a portion of the cool mixture ofshale and flue gas produced from the product separator 58. This gaspasses downwardly through the aforementioned zones in the reverse order.In the uppermost or shale ash cooling zone this gas is preheated bydirect contact with the shale ash thereby cooling the ash toapproximately atmospheric temperature. The preheated gas then movesdownwardly through the spent shale combustion zone in which hot ue gasesare generated and the carbonaceous shale is burned forming the shaleash. In the next lower or eduction zone the hot llue gases contact andeduct shale oil and gases from preheated fresh shale forming the spentcarbonaceous shale and a vapor mixture of shale oil and gas togetherwith the ilue gas. In the next lower zone, the fresh shale is preheatedby direct contact with the products of eduction thereby cooling andpartially condensing them forming a liquid oil phase and the preheatedfresh shale. The now cool gas phase continues downwardly and the liquidproduct runs downwardly by gravity filling the lower portion ofdis'rigagin'g section 12 approximately to level 50 at the lowerextremities of slots 52 which extend around the upper periphery ofdisengaging section 1.2. This liquid product fills feeder case 14 andstands up to level 50 in shale feed hopper 20 sealing it against entryof air. The diterence between these levels 5() and 59 corresponds to thepressure differential existing by virtue of gas flow through the shalerock bed in the apparatus. In other words, the apparatus is operatedunder a partial vacuum created by exhaust blower 52a.

By means of blower 52a the cool product gases pass from the upwardlymoving shale bed through slots 52 into eiluent manifold 54 surroundingthe disengaging section and therefrom directly into integrally attachedproduct vapor liquid separator and nes settler 5S. Herein the gases areseparated from the condensed oil. The gas phase containing smallquantities of separated oil and unagglomerated mists, iows fromseparator 58 under the influence of blower 52a through line 60 at a ratecontrolled by valve 64 and differential pressure recorder controller 66into a centrifugal separator 68. From this separator the agglomeratedoil phase is removed through line 70 and combined with the liquidproduct produced through line 62 or pumped into settler 58. Theremaining gas phase flows under the pressure exerted by blower 52athrough line 70 into any sort of nal separator 72. This latter separatormay comprise an oil wash such as in an absorber, an electrostatic orultrasonic treatment to clean up any residual dusts and oil mists, orother suitable separators. Oil recovered is removed through line 73.Through line 74 of oil-free gas is discharged to the atmosphere, orrecirculated in part to the kiln as previously described.

The oil phase overowing from disengaging section 12 through slots 52 owsthrough manifold 54 directly into the integrally attached settler 58,and in a serpentine path around bailes 56. The oil temperature is about120 F. and sucient settling time is provided to permit gravitation ofall solids fines larger than microns. These solids are collected inscrew conveyors 82, 84, and 86 and are returned in the manner describedbelow to hopper 20. Settler S8 is provided with overflow Weir box 57 andWeir 59 into which the product oil ows. It is pumped therefrom throughline 60' by pump 64 at a rate suicient to supply all oil recycle streamsthrough line 65, such as that to feeder case 14, and produce a net oilproduct through line 62 at a rate controlled by valve 66 and liquidlevel controller 68.

A small quantity of shale fines is invariably present in the unscreenedraw shale fed to the unit. Further, a small quantity of additional nesis unavoidably formed during the feeding of shale upwardly to theapparatus. For the most part these fines in the present apparatus passupwardly together with the oil-wet shale rock successively throughdisengaging zone 12 into retort 10 wherein the vshale fines are retortedalong with the larger shale particles. However a minor portion of thefines associated with the upwardly moving bed of rock nearest theperiphery of the bed discharge at least in part with the oil and gasthrough slots 52 into eiiluent manifold 54. This quantity of fines soentering manifold 54 is only about 5% of the fines introduced upwardlyfrom feeder case 14 with the upwardly moving mass of rock.

In the present apparatus the shape of manifold 54 and theseparator-settler vessel S8 surrounding the perforated disengagingsection 12 is especially designed to provide for the natural gravitysettling of these fines downwardly through the body of oil containedtherein so as to accumulate in a pair of horizontal parallel primaryfeeder screws 82 and 84 and a secondary screw 86. The feeder screw case84 is apparent in Figure l, and all three are readily apparent inFigures 2 and 3 to which reference will subsequently be made. Theseparator-settler vessel bottom is W-shaped and consists of a pair ofadjacent V-shaped troughs with the primary feeder screws 82 and 84disposed horizontally along the bottom or apex of each trough. Thesetroughs are closed at each end and the disengaging section 12 which isconical in fonm passes upwardly through the adjacent connecting sides ofthese troughs in the manner shown in the drawings. Thus the ines whichfall through the slots in one side of disengaging section 12 settle inone trough and the nes falling from the other side settle in the othertrough. By gravity they progress toward the primary screws 82 and 84 andare moved thereby in the same direction to a collection or secondaryscrew 86 disposed at right angles to the primary troughs at a pointadjacent and above feed hopper 20. Fines falling through slots 52 abovethe hopper fall directly into the secondary screw conveyor 86.

The slurry of shale iines discharges from the end of each primary feederscrew 82 and 84 into the outside ends of the collection screw 86. Thecollection screw 86 consists of approximately equal lengths ofright-hand and left-hand screws disposed on a common shaft so thatrotation of the shaft in the proper direction brings each of theseslurries discharged from the primary screw feeders toward a centralpoint along the length of the collection screw. This slurry at thispoint drops by gravity through dip leg S8 directly into the feedertrough 20. Dip leg 88 is sealed against inliow of air by means of liquidlevel S0. The raw shale moves into hopper 20 around dip leg 88 and isfed as previously described upwardly with the recirculated ines throughthe apparatus by means of the oscillating reciprocating piston feeder.

Referring now more particularly to Figure 2, a view taken toward hopper20 in Figure l is shown, showing the upper portion of feeder case 14,the whole vertical extent of disengaging section 12, and the lowerportion of kiln including jacket 38 and fins 36. The slots 52 ofdisengaging section 12 is indicated in broken lines. Weir box 57 shownin Figure l is also indicated with outlet line 60. The double V-shapedtrough structure of settler 58 communicating with the eluent manifold 54of Figure 1 is clearly shown in this figure. Primary screw feeders 82and 84 run lengthwise along the lower edges of these two troughs asindicated and discharge the slurry of fines through connections 92 and94 into each extreme end of of collection screw 86. Depending from acentral point along the length of collection screw feeder 86 is dip leg88 which is sealed at its lower end in liquid product oil in shalehopper 20. The nes slurry is thus returned for re-introduction into theapparatus.

Referring finally to Figure 3, a plan view of the apparatus of Figure 2is shown looking downwardly from a level just below the perforations 52.In this ligure feeder case 14, the piston 16, lower part of disengagingsection 12, and shale hopper are apparent at the bottom of theapparatus. Primary screw feeders 82 and 84 are shown running parallelalong the lower apex of each of the V-shaped troughs. The end closures96, 98, and 100 of separator-settler 58 are shown. To facilitateillustration small arrows indicate in Figure 3 the ow direction of iinessettling on the inner surfaces 104, 106, 108, and 110 and the ends ofthe two V-shaped troughs. The central curve 112 is the line ofintersection of conical disengaging section 12 with the two adjoiningsurfaces 106 and 108 of the V-shaped troughs.

'I'he discharge ends 114 and 116 of primary feeder screws 82 and 84 areshown disposed above the extreme ends of collection feeder screw 86. Thelong arrows 118 and 120 indicate the direction of fines slurry movementin the primary feeder screws and long arrows 122 and 124 indicate thedirection of slurry movement toward a central point in collection screwfeeder 86. The upper inlet opening of dip leg 88 is indicated at 126.

The apparatus of the present invention employed a feeder piston 5.5 feetin diameter and the rated shale capacity was 350 tons per day. Thedisengaging section and an upper diameter of .15 feet. The kiln section10` was 12 feet high, with diameters of l5 feet at the bottom and 18feet at the top. The efhuent manifold 54 and separator-settler 58 vesselaccording to this invention in this installation was constructedsubstantially as shown in Figure 2 and Was provided with two V-shapedtroughs coinciding at their nearest edges and closed at their extremeends. An area of 70 square feet for fines settling was provided and nofines larger than 120 microns appeared in the oil product. The settlerwas provided along the lower apex axes with two primary screws whichwere l0 inchesl in diameter and 20 feet long. These screws turned atapproximately 5 r.p.m. discharging shale fines slurry into a collectionscrew feeder of the same diameter and 10 feet long turning at 5 r.p.m.The screw conveyor in feeder case 14 was 6 inches in diameter and l5feet long and turned at 5 r.p.m. The fines slurry was successfullyreturned at a rate corresponding to about 5 percent of the rate at whichthe apparatus processed shale fines. The operation was completelysuccessful and no accumulation of shale fines in the apparatus wasnoted.

It is important in the construction of this apparatus to maintain thedownward slope of the sides and of the end closures of the W-shaped andV-shaped troughs in the separator-settler and feeder case suicientlyhigh so as to eliminate completely the possibility of nes settling andhanging up on these surfaces. To insure that the nes so contacting thesesurfaces will slide downwardly toward the primary screws, these surfacesshould describe an angle with respect to a horizontal plane of at least45 degrees and preferably above about 55 degrees. Angles greater thanabout degrees however are unnecessary and will only unduly increase theheight of the apparatus.

Again it should be emphasized that although the foregoing detaileddescription has been conducted in terms of the production of shale oiland gas from oil shale, the present process and apparatus is clearlyapplicable to other solids-fluid contacting processes in which a liquidproduct is produced during a reaction or contact between moving solidsand a Huid and in which solids fines rnust be thoroughly treated. Asstated above, the process is applicable with advantage to the treatmentof such solids as oil shale, tar sand, bituminous and sub-bituminouscoals, bitumen-saturated diatomite or other solids.

A particular embodiment of the present invention has been hereinabovedescribed in considerable detail by way of illustration. It should beunderstood that various other modifications and adaptations thereof maybe made by those skilled in this particular art without departing fromthe spirit and scope of this invention as set forth in the appendedclaims.

We claim:

1. In an apparatus wherein fines-containing solids are passed downwardlythrough a hopper and upwardly successively through a feeder, aperforated disengaging section and a contacting section; and fluidscomprising liquids and gases are passed downwardly in countercurrentcontact with said solids through said contacting section and saiddisengaging section, the improvement which comprises a manifold-settlingsection surrounding the perforations in said disengaging section andextending laterally in a direction away from said hopper, saidmanifold-settling section having a substantially horizontal W- shapedbottom consisting of a pair of adjacent V-shaped troughs extending alongsubstantially the entire length of said manifold-settling section fromthe lateral extension thereof to the end adjacent said hopper, thetroughs having sides describing an angle of at least 45 with thehorizontal so as to permit nes escaping from said perforations to settledirectly to the bottom of said troughs, fines conveyor means at thebottom of each trough for transferring settled lines to a yines outlet,and a plurality of vertical baifles in the lateral extension of saidmani- 12 was 8 feet high having a lower diameter of 5.5 feet 75fold-settling section, said baffles being displaced with respect to eachother so as to form a serpentine path for liquid flow from thedisengagng section toward a liquid outlet near the extended end of saidmanifold-settling section.

2. An apparatus according to claim 1 in combination with means forseparating said liquids from said gases in said manifold settlingsection.

3. An apparatus according to claim 1 in combination a feeder enclosurecase provided with a V-shaped trough extending along the bottom of saidfeeder case toward an outlet therefrom, a screw conveyor disposed alongthe bottom of said trough, and means for pumping a slurry of lines fromthe end of said trough to said hopper.

4. An apparatus according to claim 1 wherein the means for transferringnes to said outlet for recycle to 15 2,640,019

8 said hopper comprises a collection conveyor provided with a left-handscrew through one half of its length and a right-hand screw through theremaining length, and an outlet line from said collection screw openingfrom adjacent the point at which said left-hand and right-hand screwsmeet and discharge directly to said hopper.

References Cited in the tile of this patent UNITED STATES PATENTS1,404,873 McGee Jau. 31, 1922 2,210,362 Devenish Aug. 6, 1940 2,501,153Berg Mar. 21, 1950 2,640,014 Berg u May 26, 1953 Berg May 26, 1953

1. IN AN APPARTUS WHEREIN FINES-CONTAINING SOLIDS ARE PASSED DOWNWARDLYTHROUGH A HOPPER AND UPWARDLY SUCCESSSIVELY THROUGH A FEEDER, APERFORATED DISENGAGING SECTION AND A CONTACTING SECTION; AND FLUIDSCOMPRISING LIQUIDS AND GASES ARE PASSED DOWNWARDLY IN COUNTERCURRENTCONTACT WITH SAID SOLIDS THROUGH SAID CONTACTING SECTION AND SAIDDISENGAGING SECTION, THE IMPROVEMENT WHICH COMPRISES A MANIFOLD-SETTLINGSECTION SURROUNDING THE PERFORATION IN SAID DISENGAGING SECTION ANDEXTENDING LATERALLY IN A DIRECTION AWAY FROM SAID HOPPER, SAIDMANIFOLD-SETTLING SECTION HAVING A SUBSTANTIALLY HORIZONTAL WSHAPEDBOTTOM CONSISTING OF A PAIR OF ADJACENT V-SHAPED TROUGHS EXTENDING ALONGSUBSTANTIALLY THE ENTIRE LENGTH OF SAIDD MANIFOLD-SETTLING SECTION FROMTHE LATERAL EXTENSION THEREOF TO THE END ADJACENT SAID HOPPER, THETROUGHS HAVING SIDES DESCRIBING AN ANGLE OF AT LEAST 45* WITH THEHORIZONTAL SO AS TO PERMIT FINES ESCAPING FROM SAID PERFORATIONS TOSETTLE DIRECTLY TO THE BOTTOM OF SAID TROUGHS, FINES CONVEYOR MEANS ATTHE BOTTOM OF EACH TROUGH FOR TRANSFERRING SETTLED FINES TO A FINESOUTLET, AND A PLURALITY OF VERTICAL BAFFLES IN THE LATERAL EXTENSION OFSAID MANIFOLD-SETTLING SECTION,SAID BAFFLES BEING DISPLACED WITH RESPECTTO EACH OTHER SO AS TO FORM A SERPENTINE PATH TOR LIQUID FLOW FROM THEDSIENGAGING SECTION TOWARD A LIQUID OUTLET NEAR THE EXTENDED END OF SAIDMANIFOLD-SETTLING SECTION.